Using firebase as plugin in Quasar 0.15

I’m trying to add firebase as plugin following the guide http://quasar-framework.org/guide/app-plugins.html like it explains in the axios example. But I don’t have positives results. When I try to call firebase.auth() from my router I get a console error saying that this.$auth is undefined.

My firebase.js plugin:

// import something here
import * as firebase from ‘firebase’

// leave the export, even if you don’t use it
export default ({ router, Vue }) => {
// something to do